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Define: root hairs

tubular outgrowths of epidermal cells of the root; greatly increase the absorbing surface of the root

Define: endodermis

a single layer of cells forming a sheath around the vascular region in roots and some stems; the endodermal cells area characterized by a Casparian strip w/in radial and transvers walls. In roots and stems of seed plants, the endodermis is the innermost layer of the cortex

Define: casparian strips

a bandlike region of primary wall containing suberin and lignin; found in anticlinical - radial and transverse - walls of endodermal and exodermal cells

Define: pericycle

a tissue characteristic of roots that is bounded externally by the endodermis and internally by the phloem

Define: simple leaf

an undivided leaf; as opposed to a compound leaf

Define: midrib

the central. usually the most prominent, vein of a leaf or leaf-like organ

Define: veins

a vascular bundle forming a part of the framework of the conducting and supporting tissue of a leaf or other expanded organ

Define: compound leaf

a leaf whose blade is divided into several distinct leaflets

Define: pinnate net venation

one large central vein (midrib) present w/smaller lateral veins that diverge in pairs or pair-like manner, each on the opposite side of the midrib

Define: palmate net venation

several main veins of equal size diverge from the petiole where it joins the lamina

Define: root hairs

tubular outgrowths of epidermal cells of the root; greatly increase the absorbing surface of the root

Define: endodermis

a single layer of cells forming a sheath around the vascular region in roots and some stems; the endodermal cells area characterized by a Casparian strip w/in radial and transvers walls. In roots and stems of seed plants, the endodermis is the innermost layer of the cortex

Define: casparian strips

a bandlike region of primary wall containing suberin and lignin; found in anticlinical - radial and transverse - walls of endodermal and exodermal cells

Define: pericycle

a tissue characteristic of roots that is bounded externally by the endodermis and internally by the phloem

Define: simple leaf

an undivided leaf; as opposed to a compound leaf

Define: pinnately compound

has elongated central rachis (midrib) to which leaflets are attached opposite one another along its length - a terminal leaflet is often present at the tip of the rachis

Define: rachis

main axis of a spike; the axis of a fern leaf (frond), from which the pinnae arise; compound leaves, the extension of the petiole corresponding to the midrib of an entire leaf, this is commonly seen as the structure to which leaflets are attached

Define: palmately compound

rachis is not elongated and the leaflet are closely attached to it at one locus

Define: venation

pattern of veins in the leaf

Define: net venation

shape in which the veins are structured

Define: parallel venation

major and minor veins run parallel to one another- these area interconnected by Commisural Bundles which diverge at angles approaching 90 degrees. This is the most common pattern used to describe venation in MONOCOTS

Define: lamina or blade

flat part of the leaf

Define: petiole

stem like structure which attaches the lamina and the stem

Define: axil

upper angle where the petiole meets the stem

Define: simple leaf

has only ONE lamina/blade

Define: compound leaf

has several lamin/blade attached to one petiole

each unit is called a leaflet

Define: phyllotaxy

the arrangement of leaves on a stem

Define: alternate

leaf arrangement in which there is one bud or one leaf at a node, so the leaves alternate along the stem

Define: opposite

leaves occuring in pairs at a node, leaves are opposite one another along the stem

Define: whorled

arrangement of three or more leaves or floral parts in a circle at a node

Define: sessile

attached directly by the base; referring to a leaf lacking a petiole of to a flower or fruit lacking a pedicel

Define: stipule

an appendage, often leaflike, tha occurs on either side of the basal part of a leaf, or encircles the stem, in many kinds of flowering plants

Define: pubescence

a covering of soft short hairs

Define: prickles

a hard, pointed outgrowth from the surface of a plant, involving several layers of cells but no containing a vein

Define: spines

a hard, sharp pointed structure; usually a modified leaf, or part of a leaf

Define: thorns

a hard, woody, pointed branch

Define: tendrils

a modified leaf or part of a leaf or stem modified into a slender coiling structure that aids in support of the stems; tendrils occur only in some angiosperms

Define: leaf abscission

the dropping of leaves, flowers, fruits, or other plant parts, usually following the formation of an abscission zone

Define: leaf scar

a scar left on a twig when a leaf falls

Define: vascular bundle scar

look up . . .

Define: terminal bud

is the primary growing point at the apex of the stem (top)

Define: leaf trace

that part of a vascular bundle extending from the base of the leaf to its connection w/a vascular bundle in the stem

Define: leaf anatomy

the leaf is the primary photosynthetic organ of the plant, the makeup of the plant is key to understanding the plants genetic makep

Define: upper epidermis

lignifies xylem are situated toward the upper epidermis

Define: lower epidermis

the phloem is located the lower epidermis

Define: stomata

a minute opening, bordered by guard cells, in the epidermis of leaves and stems through which gases pass; also used to refer to the entire stomatal apparatus - the guard cells plus their included pore

Define: mesophyll

the ground tissue of a leaf, located between the layers of epidermis; meophyll cells generally contain chloroplasts

Define: palisade parenchyma

a leaf tissue composed of columnar chloroplast-bearing parenchyma cells w/their long axes at right angles to the leaf surface

Define: spongy parenchyma

a leaf tissue compsed of loosely arranged, chloroplast-bearing cells

Define: vascular bundles

a strand of tissue containing primary xylem and primary phloem (and procambium if still present) and frequently enclosed by a bundle sheath of parenchyma or fibers

Define: bundle sheath

layer or layers of cells surrounding a vascular bundle; may consist of parenchyma or sclerenchyma cells, or both

the loss of water vapor by plant parts; most transpiration occurs through stomata

Define: root pressure

the pressure developed in roots as the result of osmosi, which causes guttation of waterfrom leaves and exudation from cut stumps

Define: guttation

the exudation of liquid water from leaves; caused by root pressure

Define: translocation

in plants, the long-distance transport of water, minerals, or food; most ofter used to refer to food transport

Define: phloem loading

the process by which substances (primarily sugars) are actively secreted into the sieve tubes

Define: osmosis

the diffusion of water, or any solvent, across a selectively permeable membrane; in the absence of other forces, the movement of water during osmosis will always be from a region of greater water potential to one of lesser water potential